A type of reaction-propulsion engine to propel rockets in space,a stream of positive ions is accelerated to a high velocity by an electric field.是什么意思_A type of reaction-propulsion engine to propel rockets in space,a stream of positive ions is accelerated to a high velocity by an electric field.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句